WeatherBug Gustav Technical Discussion 7pm:8/31 update

Gustav remains a category 3 hurricane, and late afternoon satellite imagery continues to show signs of reorganization and intensification. Outer rain bands showing on radar near the mouth of the Mississippi River and off the Gulf Coast of Florida

Today, we discovered a site by Andy Carvin dedicated to providing the very latest information about Hurricane Gustav including a Wiki which can help facilitate communications. You can check it out here.

Andy had asked us to come up with a web widget/graphic which has the latest status on hurricane Gustav. If you want to include this widget on your own site you can include the following code for a large image:

Or the following code for a thumbnail image:


Click the Image for more information and the WeatherBug Hurricane Command Center

Now, here is your 5pm technical update from WeatherBug Meteorologist Joe Bartosik:

Satellite imagery over the past 6 hours, continues to show a very ragged Gustav. That said, however, there remain distinct signs that the hurricane continues to try to strengthen. First, outflow in the upper-levels of the atmosphere has become better defined on the southern half of the system. The evacuation of the air in all quadrants allows for greater inflow in the low-levels, and thus a lower pressure. This is being confirmed by United States Air Force Reserve Hurricane Hunter aircraft. At 11 a.m. EDT, the pressure was measured at 962 mb, but this lowered to 960 mb at 2 p.m. EDT, and now the plane has recorded that the pressure has dropped to 957 mb. As a result of the lowering pressure, maximum sustained wind speeds remain near 115 mph.

The eye still remains very rugged and elliptical, but as the intense convection (noted earlier on the west and southwest side of the hurricane) continues to wrap around the south side and eventually over to the east side of the hurricane, the eye should become much better defined. I believe this may be the case over the next 3 to 6 hours. If that indeed happens, then Gustav will have become a much more symmetric system and I would expect strengthening to begin to occur. Also, tropical systems tend to develop more convection during the overnight hours, so additional strengthening to Category 4 status remains a distinct possibility.

Movement remains steadily toward the northwest (320 degrees) at around 18 mph, still bringing it on a path that would mean a more direct hit on New Orleans. As noted before, this remains slightly to the right of the official NHC forecast track, and also slightly faster than what forecasts have called for over the past 24 hours.

Forecast models and NHC forecasts continue to indicate that the storm will undergo a fade to the west and more of a 300 degree heading that would take the center into central Louisiana on the Gulf Coast south of New Orleans, and about 50 to 75 miles to the west of the Mississippi River Delta. This slow shift in the track should begin to become apparent in the next 6-12 hours and should be watched closely using satellite imagery.

Regardless of the actual landfall position of the center, the Mississippi Delta, including New Orleans will likely be hit by some of the strongest winds that surround the center. At this intensity, damage will be significant and extensive.

The overall wind swath radius extends further NE of the center due to the wind speed that is added due to the forward motion of the storm which is significant at 18 mph. Currently, tropical storm force winds extend out nearly 200 miles northeast of the center. In addition to the winds, areas to the east (or right) of where the center/eye comes ashore will experience a storm surge of 12 to 20 feet. This is important for locations that are east/northeast of the center at landfall to follow closely.

The other important aspect of the storm will be the forecasted slowing that is expected to occur after landfall as the storm runs into a strong ridge of high pressure that is building over the southern states. This will cause Gustav to spend several days dumping rain over Louisiana and eastern Texas. There will be rainfall potential of 5 – 15” of rain in Louisiana, southern Alabama and Eastern Texas with some areas potentially receiving 2 feet of rain over the next week.

At 5 p.m. EDT, the center of Gustav was located at 26.4N, 87.3W and 215 miles south-southeast of the mouth of the Mississippi River. Maximum sustained wind estimates are 115 mph with gusts to 140 mph and a central pressure of 28.26” (957mb).

Pleases refer to WeatherBug News for complete coverage of the storm – http://weather.weatherbug.com/hurricanes/hurricane-Gustav-2008.html